Five copies of the UAS regulatory sequence drive expression of a 'DenMark' dendritic marker which contains a non-fluorescent 'spaghetti monster GFP' ('smGdP') marker inserted between the transmembrane domain and the extracellular domain of Mmus\Icam5. The smGdP marker consists of 10 copies of the Tag:V5 tag inserted in groups into the backbone of a superfolder green fluorescent protein which has been rendered non-fluorescent by mutation and the open reading frame has been optimised for Drosophila codon usage.